15-317 Constructive Logic
Lecture 2: Natural Deduction

We define the meaning of the usual connectives
of propositional logic (conjunction, implication, disjunction) by
rules that allow us to infer when they should be true, so-called
introduction rules. From these, we derive rules for the use of
propositions, so-called elimination rules. The resulting
system of natural deduction is the foundation of intuitionistic
logic which has direct connections to functional programming and logic
programming.